Martin - the author of original novels A Song of Ice and Fire - explained why he decided to kill off the character in this manner.

"I knew all along when and how Joffrey was going to die, and on what occasion," he told Entertainment Weekly. "I'd been building up to it for three years through the first books.

"Part of it was that there's a lot of darkness in the books. I've been pretty outspoken in my desire to write a story where decisions have consequences and no-one is safe. But I didn't want it to be unrelentingly bleak - I don't think everyone would read the books if everything was just darkness and despair, and people being horribly tortured and mutilated and dying.

"Every once in a while you have to give the good guys a victory - where the guys who are perhaps a lighter shade of grey have a victory over the guys who are a darker shade of grey. The Red Wedding and this - fans call this the Purple Wedding - occur in the same book. In the TV show, it's separate seasons.

"But Joffrey's death was in some ways a counterweight for readers to the death of Robb and Catelyn. It shows that yes, nobody is safe - sometimes the good guys win, sometimes the bad guys win. Nobody is safe, and that we are playing for keeps. I also tried to provide a certain moment of pathos with the death."

On why he did not die at the hands of one of the Starks, he said: "I wanted to make it a little bit unclear what exactly has happened here, make the readers work a little to try and figure out what has happened. And of course, for Tyrion, Joffrey's death doesn't make things better, it makes things worse.

"Tyrion's in terrible trouble, and it proves that something I've tried to make a point of through the whole series: decisions have consequences. When Robb breaks his word to House Frey and doesn't marry one of Frey's daughters, that has dire consequences for him."

He added: "One of Tyrion's problems has been that he has a big mouth. He's been saying things since the beginning of the series, these veiled threats to Cersei - 'Someday I'm going to get you for this, someday your joy is going to turn to ashes in your mouth'. Now, all these declarations make him look really guilty."

Game of Thrones continues next Sunday (April 20) on HBO in the US and the following day on Sky Atlantic in the UK.